Cyclone dust collector having a wear shield



Dec. 28, 1965 w. E. ARCHER CYCLONE DUST COLLECTOR HAVING A WEAR SHIELDFiled Oct. 9. 1962 )S IO W 14 PR/m 4/er HG]. Hem ARI INVENTORZ WILLIAME. ARCHER ATTORNEY United States Patent C) 3,225,525 CYCLONE DUSTCQLLECTOR HAVING A WEAR SELD William E. Archer, Portuguese Bend, Calif.,assignor to Joy Manufacturing Company, Pittsburgh, Pin, a corporation ofPennsylvania Filed Oct. 9, 1962, Ser. No. 229,415 6 Claims. (Cl. 55346)This invention relates to a particle collector and more particularly toa Wear shield mounted on a portion of each outlet tube in the firs-t rowof outlet tubes in a multi-row, multiple unit cyclone type collector toprotect such first row of tubes from the wearing effect of abrasiveparticles in an incoming stream of gases having abrasive particlesentrained therein.

It is common practice in mechanical collectors having outlet tubes,extending into the path of the stream to be cleaned, to protect theleading face of the first row of outlet tubes with a wear shield whenabrasive particles are entrained in the stream to be cleaned. It is alsoknown that one factor in determining the wear rate of a surface exposedto a stream of dusty gases having abrasive particles entrained thereinis the size of the angle of impingement (the acute angle between thedirection of the flow of gases and the surface on which the wear istaking place). An investigation by R. L. Stoker titled, Erosion Due toDust Particles in a Gas Stream, and published in Industrial andEngineering Chemistry, volume 41, page 1196, June 1949, showed thatblack iron exposed to a jet of air containing silica-sand had a maximumwear rate at an impingement angle of approximately 20 with relativelyhigh wear rate for all angles between 15 and 55 as compared with therate of wear at an impingement angle of 90. From this and other studiesit is apparent that the desirable angles of impingement would be eithervery small, in the range from to 15, or very large, in the range of 60to 90. The wear shield of the present invention provides these desirableimpingemen-t angles.

Accordingly, one object of this invention is to provide a new andimproved particle collector having a wear shield mounted on a portion ofan outlet tube to protect such tube from the wearing effect of abrasivedust in an incoming stream of gases having abrasive particles entrainedtherein.

Another object of this invention is to provide a new and improved wearshield.

It is a further object of this invention to provide a new and improvedparticle collector having a wear shield mounted on a portion of eachoutlet tube in a first row of outlet tubes in a multi'row, multiple unitcyclone type dust collector to protect such tubes from wearing effect ofabrasive dust in an incoming stream of dusty gases, said wear shieldhaving a surface which yields an impingement angle with the stream ofdusty gases greater than 60 on a main portion of such surface and lessthan 15 on subsidiary portions of such surface.

These and other objects and advantages of this invention will becomemore apparent upon consideration of the following description anddrawings in which:

FIG. 1 is a schematic representation of a multi-row, multiple unit,cyclone type dust collector having wear shields constructed according tothe principles of this invention mounted on each tube of the first rowof outlet tubes, respectively;

FIG. 2 is a sectional view taken substantially along the line 22 of FIG.1;

FIG. 3 is a sectional view taken along line 33 of FIG. 1;

FIG. 4 is a sectional view similar to FIG. 3 showing a 3,225,525Patented Dec. 28, 1965 "ice second embodiment of the wear shield of thisinvention;

FIG. 5 is a sectional view similar to FIG. 3 showing a third embodimentof the wear shield of this invention;

FIG. 6 is a sectional view similar to FIG. 3 of a Wear shield of theprior art; and

FIG. 7 is a sectional View of a second wear shield of the prior art.

In FIG. 1 there is shown a multi-row, multiple unit, cyclone type dustcollector of a type Well known in the art generally indicated at 10 andcomprising a formed closed housing 11 having an upper portion 15 mountedon a downwardly tapering lower portion or hopper 21. The upper portion15 communicates with an inlet duct 12 connected to a source of dustygases (not shown) and also communicates with an outlet duct 14 connectedto a chimney or other disposal means (not shown) the upper portion 15 ofthe housing 11 is divided into an outlet chamber 17 and an inlet chamber18 by a slanting divider plate 16 extending completely across the upperportion 15, internally. The upper portion 15 is divided from the hopper21 by a horizontal header plate 19 having a plurality of bores each ofwhich communicates, and is in register, with a cyclone separator 20 of atype well known in the art arranged in a plurality of rows transverse toa stream of gases entering through the inlet duct 12 into the inletchamber 18. Each separator 20 is provided with an outlet tube 22extending upwardly through the header plate 19 and the divider plate 16to communicate with the outlet chamber 17 and the outlet duct 14.

The outlet tubes in the first row of tubes nearest the inlet duct 12 areindicated as tubes 22 and differ from the tubes 22 in that each isprovided with an elongated, channel shaped, wear shield 24 rigidlysecured to the outer surface of the tube 22' as by welding and having abase portion 25 longitudinally parallel to the axis of the tube 22' andtransversely normal to the direction of gas flow from the duct 12 ashereinafter described. The longitudinal centerline of the base portion25 and the axis of the tube 22' lie in a common plane parallel to thedirection of gas flow. The wear shield 24 also has leg portions 26normal to the base portion 25 and contacting the outer periphery of thetube 22' along circumferentially spaced lines parallel to the axis ofthe tube 22. The wear shield extends longitudinally along the tube 22from the divider plate 16 to a point upwardly spaced from the headerplate 19 by an amount sufiicient to allow unimpeded gas flow into thecyclone separator 20 of which the respective outlet tube 22' is a part.

It is to be noted that in the preferred embodiment as shown in FIG. 3the width of the base portion 25 is equal to approximately /6 thediameter of the tube 22'. This ratio is preferred as it is large enoughto adequately protect the tube and uses a minimum of material for suchprotection. Wear shields having this ratio of width to diameter alsoprovide better gas flow than those having a higher ratio since less areaof flat surface is opposed to the gas flow. It is further to be notedthat the leg portions 26 shown normal to the base portion 25 can beoblique to the base portion 25 spreading to a maximum width equal to thediameter of the tube 22.

In operation of this device a stream of gases having finely divided,solid particulate matter entrained therein enters the chamber 18 of thedust collector 10 from the inlet duct 12 travelling in the directionindicated by an arrowed line 28 in FIG. 3. The entrained particlesimpinge upon the wear shield at an impingement angle of approximately asindicated by the are 29, with relation to the base portion 25 of wearshield 24. It will be obvious that the impingement angle of theentrained particles with relation to the leg portions 26 will be approximately and that angles of impingement between the entrainedparticles and any portion of the tube 22' exposed to the direct actionof the stream of gas will be in the range between the 0 and 15 Since allof the impingement angles of the entrained particles with respect to thewear shield 24 and tube 22' constructed according to the principles ofthis invention are either approximately 90 or less than 15 optimumconditions for the reduction of the rate of wear are present and thetube and wear shield of this invention will have a much greater usefullife than those of the prior art.

Such a prior art device is shown in FIG. 6 wherein an outlet tube 32 isprovided with an angle type wear shield 33 having leg portions 34 normalto each other. An arrowed line 35 illustrates the direction of gas flowwhile an are 36 indicates the size of the impingement angle ofparticulate matter, entrained in the gas, against the leg portion 34 ofthe wear shield 33. It is to be noted that the impingement angle 36 isapproximately 45 and according to the above cited report is within therange of angle wherein relatively rapid wear takes place as comparedwith angles greater than 55 or less than 15 and it is obvious that thedevice of FIG. 6 would have substantially shorter useful life than thatof FIG. 3.

In FIG. 4 there is shown a second embodiment 24 of the wear shield ofthis invention in which the leg portions 26 of the channel are providedwith L-shaped extensions 40 having a base portion extending outwardly atright angles to the leg portion 26 and leg portions extending forwardlyin the direction of the gas flow, as shown by an arrowed line 38, untilsuch leg portions contact the tube 22 upon which the wear shield 24' isrigidly secured in the same manner as was the wear shield 24. For thewear shield 24 the width of the base portion 25' and of the L-shapedextensions 40 is determined by the diameter of the tube 22'. The baseportion 25' having a width equal to approximately /3 of the diameter ofthe tube and extensions 40 each having a width of of the tube diameter.This results in a total Width of the wear shield equal to /6 of thediameter of the tube. The flat surface area opposed to the gas flow isbroken up into portions spaced longitudinally of the gas flow therebyhaving less resistance to such flow, as is known. Inspection of the FIG.4 drawing shows that the impingement angle as indicated by an are 39will be the same for the embodiment of FIG. 4 as for that of FIG. 3 withthe attendant advantage of low rate of wear and extended useful life.

FIG. 5 shows a third embodiment of the principles of this invention inan elongated wear shield 42 having an arcuate cross section with aconcavo-convex base portion, the inner surface of which is mated to theouter surface of the outlet tube 22' and having along its longitudinaledges radially outwardly extending portions 43. Preferably the greatesttransverse dimension across portions 43 is equal to the diameter of thetube 22. With the direction of the gas flow as indicated by an arrowedline 44 the effective impingement angle is that indicated by an are 45between the arrowed line 44 and a line 46 drawn tangent to the outersurface of the wear shield 42 from the rearmost point of the portion 43.It is to be noted that the angle 45 is approximately 70 which is withinthe 60 to 90 range cited as being desirable in the above mentionedreport. The angle 45 is the effective impingement angle for all portionsof the wear shield 42 between the point of tangency of the line 45 withthe outer surface of the wear shield 42 and the outwardly extendedportion 43. It is obvious that all other impingement angles between thewear shield 42 and the entrained particles in the gas stream travellingin the direction indicated by the arrowed line 44 will be greater than70 with the consequent reduction rate of wear and extension of usefullife hereinbefore cited as advantages residing in the wear shields ofthis invention.

FIG. 7 shows an arcuate wear shield 48 of the prior art similar to thewear shield 42 of this invention excepting that the outwardly extendingportions 43 have been omitted. An arrowed line 50 and an are 51indicates the direction of gas flow and the impingement angle,respectively, for a portion of the gas stream and entrained particlesimpinging upon the wear shield 48. It is to be noted that the angle 51is in the range between 45 and 15 cited in the above mentioned report asyielding high rates of wear common to the. wear shields of the priorart.

Preferred embodiments of this invention having been described andillustrated it is to be realized that modifications thereof can be madewithout departing from the broad spirit and scope of this invention. Itis therefore respectfully requested that this invention be interpretedas broadly as possible and be limited only by the prior art.

What I claim is:

1. In a cyclone collector of the class having multiple rows of collectorunits, each of said collector units comprising a collector tube coaxialwith a cylindrical outlet tube, said rows of collector units beingdisposed transversely of a stream of gases having abrasive particlesentrained therein, said stream of gases entering said cyclone collectorthrough an inlet connection, a first row of said collector units nearestsaid inlet connection being exposed to wearing effects of said abrasiveparticles: the improvement comprising the combination of individualelongated wear shields mounted on the upstream sides of said outlettubes, respectively, of all the collector units in said first row, eachof said wear shields having a longitudinal centerline parallel to theaxis of said outlet tube coplanar therewith and defining a common planeparallel to a flow path along which said stream of gases flows from saidinlet connection to said outlet tube, each said wear shield comprising abase portion normal to said plane and two spaced longitudinally parallelleg portions substantially parallel to said plane and equidistanttherefrom and said leg portions extending downstream from the lateraledges of said base portion far enough to make line contact with theexternal surface of said outlet tube.

2. A cyclone collector as set forth in claim 1 wherein the width of saidbase portion is equal to approximately /6 of the outside diameter ofsaid outlet tube.

3. In a cyclone collector of the class having multiple rows of collectorunits, each of said collector units comprising a collector tube coaxialwith a cylindrical outlet tube, said rows of collector units beingdisposed transversely of a stream of gases having abrasive particlesentrained therein, said stream of gases entering said cyclone collectorthrough an inlet connection, a first row of said collector units nearestsaid inlet connection being exposed to wearing effects of said abrasiveparticles: the improvement comprising the combination of individualelongated wear shields mounted on the upstream sides of said outlettubes, respectively, of all the collector units in said first row, eachof said wear shields having a longitudinal centerline parallel to theaxis of said outlet tube coplanar therewith and defining a common planeparallel to a flow path along which said stream of gases flows from saidinlet connection to said outlet tube, each said wear shield comprising abase element normal to said plane and two spaced longitudinally parallelleg elements having spaced first and third portions substantiallyparallel to said plane and respectively equidistant therefrom, saidthird portions being more remote from said plane than said firstportions, said third portions being spaced from and connected to saidfirst portions by second portions parallel to said base element andspaced downstream therefrom, said first portions of said leg elementsextending downstream from the lateral edges of said base element andsaid third portions extending downstream from the lateral edges of saidsecond portions far enough to make linecontact with the external surfaceof said outlet tube.

4. A cyclone collector as set forth in claim 3 wherein the width of saidbase element is equal to approximately /5 of the outside diameter ofsaid outlet tube and each of said second portions of said leg elementshas a width equal to A of said diameter.

5. A cyclone collector as set forth in claim 3 wherein the width of saidbase element is equal to approximately /3 of the outside diameter ofsaid outlet tube.

6. In a cyclone collector of the class having multiple rows of collectorunits, each of said collector units comprising a collector tube coaxialwith a cylindrical outlet tube, said rows of collector units beingdisposed transversely of a stream of gases having abrasive particlesentrained therein, said stream of gases entering said cyclone collectorthrough an inlet connection, a first row of said collector units nearestsaid inlet connection being exposed to Wearing eflects of said abrasiveparticles: the improvement comprising the combination of individualelongated transversely arcuate Wear shields mounted on the upstreamsides of said outlet tubes, respectively, of all the collector units insaid first row, each of said wear shields having a longitudinalcenterline parallel to the axis of said outlet tube coplanar therewithand defining a common plane parallel to a flow path along Which saidstream of gases flows from said inlet connection to said outlet tube,each said Wear shield comprising a concavo-convex base portion bisectedby said plane, said concave surface having an outside radius equal tothe radius of said outlet tube said concave surface being in generalcontact with the outer surface of said outlet tube, and two spaced legportions along the longitudinal edges of said base portion said legportions having external surfaces radial to the axis of said tube, saidleg portions extending obliquely upstream from said base portion.

References Cited by the Examiner UNITED STATES PATENTS 1,894,270 1/1933Grady 122--235 2,083,764 6/1937 Weisberger 435 2,087,464 7/1937 Ayers55-462 2,235,539 3/1941 Smith 5543S 2,544,395 3/1951 Polk 55-3483,078,919 2/1963 Brown -142 X 3,105,544 10/1963 Brown 165142 FOREIGNPATENTS 183,160 7/1922 Great Britain.

OTHER REFERENCES Industrial & Engineering Chemistry, vol. 41, June 1949,pp. 1196-1199, article titled Erosion Due to Dust Particles in a GasStream (Stoker).

ROBERT F. BURNETT, Primary Examiner.

HARRY B. THORNTON, Examiner.

1. IN A CYCLONE COLLECTOR OF THE CLASS HAVING MULTIPLE ROWS OF COLLECTORUNITS, EACH OF SAID COLLECTOR UNITS COMPRISING A COLLECTOR TUBE COAXIALWITH A CYLINDRICAL OUTLET TUBE, SAID ROWS OF COLLECTOR UNITS BEINGDISPOSED TRANSVERSELY OF A STREAM OF GASES HAVING ABRASIVE PARTICLESENTRAINED THEREIN, SAID STREAMM OF GASES ENTERING SAID CYCLONE COLLECTORTHROUGH AN INLET CONNECTION, A FIRST ROW OF SAID COLLECTOR UNITS NEARESTSAID INLET CONNECTION BEING EXPOSED TO WEARING EFFECTS OF SAID ABRASIVEPARTICLES: THE IMPROVEMENT COMPRISING THE COMBINATION OF INDIVIDUALELONGATED WEAR SHIELDS MOUNTED ON THE UPSTREAM SIDES OF SAID OUTLETTUBES, RESPECTIVELY, OF ALL THE COLLECTOR UNITS IN SAID FIRST ROW, EACHOF SAID WEAR SHIELDS HAVING A LONGITUDINAL CENTERLINE PARALLEL TO THEAXIS OF SAID OUTLET TUBE COPLANAR THEREWITH AND DEFINING A COMMON PLANEPARALLEL TO A FLOW PATH ALONG WHICH SAID STREAM OF GASES FLOWS FROM SAIDINLET CONNECTION TO SAID OUTLET TUBE, EACH SAID WEAR SHIELD COMPRISING ABASE PORTION NORMAL TO SAID PLANE AND TWO SPACED LONGITUDINALLY PARALLELLEG PORTIONS SUBSTANTIALLY PARALLEL T SAID PLANE AND EQUIDISTANTTHEREFROM AND SAID LEG PORTIONS EXTENDING DOWNSTREAM FROM THE LATERALEDGES OF SAID BASE PORTION FAR ENOUGH TO MAKE LINE CONTACT WITH THEEXTERNAL SURFACE OF SAID OUTLET TUBE.